"Before you read this paper"


It is hypothesized that changes of cis-regulatory sequences have more often contributed to the evolution of body plan than coding sequences. However, evidence for this has not been sufficiently consolidated. A recent report presents changes in a regulatory sequence associated with stepwise limb loss during snake evolution. Sonic hedgehog (Shh), a key gene in hedgehog signaling, is expressed in zone of polarizing activity (ZPA) in developing limb buds, and plays crucial role in the limb development. Only one enhancer directs the Shh expression in limb buds. Genome comparison of the enhancer sequences among snakes as well as genome edition-aided synthetic restoration of its function in mouse embryos demonstrates that the limb enhancer has progressively lost its function during snake evolution. This study clearly shows a future direction of “EvoDevo” research.

Main paper

Progressive Loss of Function in a Limb Enhancer during Snake Evolution
Cell Volume 167, Issue 3, 20 October 2016, Pages 633-642.e11
by Evgeny Z et al.